Patient support interface pressure monitoring system

ABSTRACT

An interface pressure monitoring system includes an underlayment interposed between a patient support surface and a patient supported thereon and a processor. The underlayment includes pressure sensors such as, for example, an array of piezoelectric pressure sensors. The processor acquires pressure data from the underlayment, analyzes the data and stores the analyzed data for further processing, alerting and/or reporting.

FIELD OF THE INVENTION

The present invention relates to patient care. More particularly, theinvention relates to a system and method for monitoring, mapping andtracking over time the interface pressures produced between a surfaceand patient supported thereon, the system being specifically adapted toalert the patient or a caregiver of a need for repositioning inprevention and/or treatment of tissue damage.

BACKGROUND OF THE INVENTION

As a result of disease, surgery, age, injury or other infirmity, manypatients 10 suffer such decreased mobility as to become generallyconfined to a bed 11, as depicted in FIG. 1, or a wheelchair 12, asdepicted in FIG. 3. As particularly shown in the figures, such a patient10 is generally immobilized in a fixed position atop and/or about one ormore patient support surfaces 13. For example, the patient 10 asdepicted in FIG. 1 is shown to be immobilized in a supine position 14supported on the top surface 15 of a mattress 16 while the patient 10 asdepicted in FIG. 3 is shown to be immobilized in a sitting position 17supported on and about seat bottom 18, seatback 19 and footrest 20. Inorder to maximize comfort for such immobilized patients 10, themanufacturers of hospital type beds 11 and wheelchairs 12 go to greatlengths for the development of advanced patient support surfaces 13, aparticular goal of such manufacturers being minimization of localizedinterface pressures.

Unfortunately, and notwithstanding the best efforts to date ofmanufacturers, confined or otherwise immobile patients 10 remaindangerously susceptible to the hazards of elevated interface pressures,which pressures can within a very short period of time result in tissuebreakdown leading to decubitus ulcers. In particular, as depicted inFIG. 2A, patients 10 confined to the supine position 14 are generallyplaced at heightened risk for the development of decubitus ulcers in theoccipital region 21 about the occipital bone at the back of thepatient's head; in the left and right scapular regions 22 about thepatient's scapulae, or shoulder blades; in the sacral region 23 aboutthe patient's sacrum at the lower end of the patient's vertebral column;and in the calcaneal, or calcanean, regions 24 about the patient'scalcanei, or heels.

Likewise, as shown in FIG. 2B, patients confined in a left or rightlateral position 25 are generally placed at heightened risk for thedevelopment of decubitus ulcers in the auricular regions 26 on or aboutthe patient's lower auricle—the shell-like structure on the side of thehead forming in part the external ear; in the acromial region 27 of thepatient's lower acromion or acromial process, or “point of theshoulder;” in the cubital region 28 of the patient's cubitus, or elbow,underlying the patient; in the trochanteric region 29 of the patient'slower, greater trochanter at the upper extremity of the patient's femur;in the condylar regions 30 about the patients lateral and medial condyleof tibia to the sides of the patient's knees; in the malleolar regions31 about the patient's lateral and medial malleoli, or ankles; and inthe calcaneal, or calcanean, regions 24 about the sides of the patientscalcanei, or heels.

Still further, as shown in FIG. 2C, patients confined to the proneposition 39 are generally placed at heighted risk for the development ofdecubitus ulcers in the cubital regions 28 of the patient's cubiti, orelbows; in the auricular regions 26 about the patient's auricles; buccalregions 32 about the patient's cheeks; in the nasal regions 33 about thepatient's nasus, or external nose; in the pectoral regions 34 about thepatient's breasts; in the case especially of a male patient, in thegenital region 35 about the male patient's genitalia; in the iliacregions 36 about the patient's iliac crests (the broad, flaring portionsof the hip bones); in the patellar regions 37 about the patient'spatellae, or kneecaps; and in the pedal regions 38 about the patient'stoes.

While generally more ambulatory than a bedridden patient 10, patients 10confined to wheelchairs 12, as depicted in FIG. 3, are nonethelesssusceptible to decubitus ulcers. Additionally, because the confinementof many such patients 10 is concomitant diagnoses involving sensorydegradation, such as, for example, spinal cord injuries andcomplications of diabetes, such patients 10 are often at increased riskbecause such patients 10 can easily develop an ulcer that is notdetected by the patient 10 due to lack of sensation and is also notdetected by a caregiver due to the relative independence of the patient10. In any case, as shown in FIG. 3, patients 10 confined to the sittingposition 17 are generally placed at heighted risk for the development ofdecubitus ulcers in the region 40 of the inferior angle patient'sscapula; in the spinal regions 41 particularly about the patient'sthoracic spine; the coccygeal region 42 about the patient's coccyx, ortailbone; in the ischial, or sciatic, regions 43 about the patient'sischial tuberosities, which are the main a weight-bearing points for apatient in the sitting position 17; in the plantar regions 44 about theplantar surfaces, or soles, of the patient's feet; in the calcaneal, orcalcanean, regions 24 about the patient's calcanei, or heels; and in thepedal regions 38 about the patient's toes. In the case of a patient 10so confined and also requiring a headrest or like support, the patient10 is additionally susceptible to decubitus ulcers in the occipitalregion 21 about the occipital bone at the back of the patient's head.

Regardless of location, however, it should be understood that inaddition to being extremely painful, any decubitus ulcer once formed isat best difficult and expensive to treat. Additionally, it should beclearly understood that treatment often fails, leading to rapid declineof the patient's health and ultimately, in many cases, to the patient'sdeath and/or drastically increased costs and services. As a result, anyadvance in the prevention and treatment of decubitus ulcers should beregarded as addressing a longstanding, unsolved problem.

With the foregoing background in mind, it is therefore an overridingobject of the present invention to advance the care afforded to patientsvulnerable to the formation of decubitus ulcers. In particular, it is anobject of the present invention to provide a system and method by whichexcessive interface pressures may be readily and robustly detected and,additionally, whereby the patient and/or patient's caregiver may bealerted to the need for repositioning in prevention or treatment ofinterface pressure related tissue damage. Additionally, it is an objectof the present invention to provide such a system and method that may bereadily utilized by skilled and unskilled caregivers alike. Further, itis an object of the present invention to provide such a system andmethod that also makes provision for review of the care afforded apatient, thereby not only ensuring that caregivers provide timelyintervention in response to a detected dangerous situation but alsoproviding a tool for use by a clinician evaluating the effectiveness ofpast care and need for adjustment to a treatment protocol.

SUMMARY OF THE INVENTION

In accordance with the foregoing objects, the present invention—aninterface pressure monitoring system—generally comprises an underlaymentadapted to be interposed between a patient support surface and a patientsupported thereon and a processor. The underlayment comprises aplurality of pressure sensors such as, for example, an array ofpiezoelectric pressure sensors. The processor acquires pressure datafrom the underlayment, analyzes the data and stores the analyzed datafor further processing, alerting and/or reporting.

Finally, many other features, objects and advantages of the presentinvention will be apparent to those of ordinary skill in the relevantarts, especially in light of the foregoing discussions and the followingdrawings, exemplary detailed description and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Although the scope of the present invention is much broader than anyparticular embodiment, a detailed description of the preferredembodiment follows together with illustrative figures, wherein likereference numerals refer to like components, and wherein:

FIG. 1 shows, in a perspective view, a patient as confined to bed in asupine position;

FIG. 2A shows, in a schematic diagram, the prevalent locations for theformation of decubitus ulcers, or pressure sores, in a patient confinedfor an excessive time to the supine position;

FIG. 2B shows, in a schematic diagram, the prevalent locations for theformation of decubitus ulcers, or pressure sores, in a patient confinedfor an excessive time to a lateral position;

FIG. 2C shows, in a schematic diagram, the prevalent locations for theformation of decubitus ulcers, or pressure sores, in a patient confinedfor an excessive time to the prone position;

FIG. 3 shows, in a perspective view, a patient as confined to awheelchair in a sitting position, the figure showing also the prevalentlocations for the formation of decubitus ulcers, or pressure sores, in apatient so confined;

FIG. 4 shows, in a perspective view, the preferred embodiment of theinterface pressure monitoring system of the present invention asdeployed for use in connection with a patient confined to bed;

FIG. 5 shows, in a schematic block diagram, various details of theinterface pressure monitoring system of FIG. 4;

FIG. 6A shows, in a schematic representation, a first representativemapping of patient interface pressures as detected and utilized by thepresent invention for determining the necessity of an intervention;

FIG. 6B shows, in a schematic representation, a second representativemapping of patient interface pressures as detected and utilized by thepresent invention for determining the necessity of an intervention;

FIG. 6C shows, in a schematic representation, a third representativemapping of patient interface pressures as detected and utilized by thepresent invention for determining the necessity of an intervention;

FIG. 7A shows, in a screen capture view, a first representativegraphical display as generated according to the preferred method of useof the present invention for the conveyance of useful information to apatient and/or caregiver;

FIG. 7B shows, in a screen capture view, a second representativegraphical display as generated according to the preferred method of useof the present invention for the conveyance of useful information to apatient and/or caregiver;

FIG. 8A shows, in a perspective view, a first user input device such asmay be employed in connection with at least one preferred embodiment ofthe present invention; and

FIG. 8B shows, in a perspective view, a second user input device such asmay be employed in connection with at least one preferred embodiment ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT:

Although those of ordinary skill in the art will readily recognize manyalternative embodiments, especially in light of the illustrationsprovided herein, this detailed description is exemplary of the preferredembodiment of the present invention, the scope of which is limited onlyby the claims appended hereto.

Referring now to FIGS. 4 and 5 in particular, the interface pressuremonitoring system 50 according to the preferred embodiment of thepresent invention is shown to generally comprises an underlayment 51adapted to be interposed between a patient support surface 13 and apatient 10 supported thereon and a processor 55. As shown in FIG. 4, asuitable patient support surface 13 in connection with which the presentinvention may be utilized may comprise the top surface 15 of a mattress16 of a bed or, as shown in FIG. 3, may comprise one or any combinationof the seat bottom 18, the seatback 19 or the footrest 20 of awheelchair or any other substantially equivalent patient surface. In anycase, the underlayment 51 according to the present invention comprises aplurality of pressure sensors 52 such as, for example, an array 53 ofpiezoelectric pressure sensors. While such sensors are generally knownto those of ordinary skill in the art, one example of an implementationthat may be adapted to the teachings of the present invention is foundin U.S. Pat. No. 6,720,712 B2 issued Apr. 13, 2004 to Scott et al. Bythis reference, the full disclosure of U.S. Pat. No. 6,720,712 B2 isincorporated herein as though now set forth in its entirety.

In any case, any appropriate cable 58 interconnects the electricalinterface 54 from the pressure sensors 52 to the processor 55 through aprovided electrical interface 57 to a data acquisition circuit 56provided in connection with the processor 55. In the case of animplementation of a piezoelectric sensor array 53, the data acquisitioncircuit preferably provides the input signal generator and the outputsignal processor for the piezoelectric sensor array 53, therebydistributing this hardware away from the underlayment 51 and thuspreventing the introduction of bulky and hard surfaces to the area wherepatient contact may occur.

The processor 55 further comprises a controller 59 and associatedfirmware and/or software, enabling the processor to be adapted forpressure data acquisition, analysis and storage as well as for alertingand reporting functions as will be better understood further herein. Inorder that the processor may store the acquired pressure data, however,a mass storage device 60 is provided. Although those of ordinary skillin the art will recognize many alternatives, the present inventioncontemplates the use of a solid state drive 61, which, as will beappreciated by those of ordinary skill in the art, is not only veryrugged and shock resistant, but is also beneficially a low power storagedevice. This latter feature, of course, is particularly advantageous foroperation of the interface pressure monitoring system 50 of the presentinvention on battery power such as may be required in the event of aprimary power failure or in connection with a wheelchair 12.

Still further, the processor 55 comprises a user interface 62, whichparticularly includes at least a graphic display device 72.Additionally, however, the user interface 62 for the processor 55preferably comprises one or more input and or input/output devices. Forexample, the user interface 62 may comprise a universal serial bus(“USB”) controller 63 and one or more USB ports 64 for the connection ofone or more external devices 65; an integrated card reader 73; anintegrated biometric input device 69 such as, for example, a fingerprintreader; and/or an aural output device 70 such as, for example, an audiospeaker 71, piezoelectric tone generator or the like. As shown in FIGS.8A and 8B, respectively, appropriate external input devices 65 for usein connection with the present invention may comprise, for example, aUSB keypad 66 or a USB fingerprint reader 67. In the case of theexternally provided USB fingerprint reader 67, however, it is noted thatthe most preferred implementation of the present invention contemplatesutilization of such a reader 67 as comprises a sufficiently long cable68 as to enable utilization of the reader 67 for collection of biometricidentification data from the bedridden or wheelchair bound patient 10.

In any case, and turning additionally to FIGS. 6A through 6C, theoperation of the interface pressure monitoring system 50 of the presentinvention is described. With the patient 10 resting adjacent theunderlayment 51 as previously described, the pressure sensors 52 of theunderlayment detect areas of relatively high pressure as may be expectedin the regions of bony prominences as discussed in the backgroundhereto. The detected pressure data is then transmitted to the processor55 through the data acquisition circuit 56 where under the control ofthe controller 59 and associated firmware and/or software, the acquireddata is time-stamped and mapped to its source location in theunderlayment 51 and stored in the provided mass storage device 60.

Based upon the mapping of the data, the controller 59 if possibledetermines the body position of the patient 10. For example, thepressure data as depicted in conceptual mapping of FIG. 6A clearlyindicates a patient 10 lying atop the underlayment in the supineposition. Given such a determination, the controller 59 is then able torecognize that the pressure data as depicted in the conceptual mappingof FIG. 6B represents only a migration of the patient 10 across theunderlayment 51 as opposed to an actual repositioning of the patient 10.In this manner, the controller 59 is adapted to treat a transition fromthe state of FIG. 6A to the state of FIG. 6B (or the like) as if thepatient has had no relief from the interface pressure.

In any case, the controller 59 is further adapted to monitor the lengthof time that the patient 10 remains in such a substantially unchangedposition and, upon the expiration of a threshold length of time tosignal, through the aural output device 70, a wired or wireless Ethernetconnection or the like, that a caregiver should attend to therepositioning of the patient 10. If the caregiver does not respond in atimely fashion, however, the controller 59 may also be adapted to sendan alarm to a supervisor or other authority. In any case, the controller59 and associated mass data storage device 60 is preferably adapted tomaintain an audit record of the pressures experienced over time by thepatient 10 as well as the interventions received by the patient 10. Tothis end, the processor 50 may be adapted to require identification ofthe caregiver and/or the patient 10 prior to or upon the taking of anaction respecting the care of the patient. In implementation of thisfeature, the previously described keypad 65, fingerprint readers 67, 69and/or integrated card reader 73 may be conventionally utilized.

Referring then to FIG. 6C, however, it may be that the patient 10 ispartially ambulatory or that it is desired that the controller 59autonomously determine an adequate repositioning of the patient 10. Inany such case, the controller 59 is adapted to “reset” to zero thetracked time in position of the patient 10. To this end, the previouslydiscussed body position determination feature of the present inventionmay be utilized to determine that, as depicted in the conceptual mappingof FIG. 6C, the patient has been rolled into the left side lateralposition.

Referring further still to FIGS. 7A and 7B, it is shown that thedescribed body position determination feature is also particularlyadvantageous in providing an image through the display 72 that may bereadily interpreted by a layperson in the role of caregiver. As shown inthe figures, the display preferably shows an overhead view of thepressure mapping of the underlayment 51 as well as a plain languageindication of the locations of heighten pressures as determined by thecontroller 59. These displays may then be used by the laypersoncaregiver to doubly ensure proper care of the patient 10.

While the foregoing description is exemplary of the preferred embodimentof the present invention, those of ordinary skill in the relevant artswill recognize the many variations, alterations, modifications,substitutions and the like as are readily possible, especially in lightof this description, the accompanying drawings and claims drawn thereto.For example, those of ordinary skill in the art will recognize, in lightof this exemplary description, that the keypad 65, fingerprint readers67, 69 and/or integrated card reader 73 are preferably utilized to “lockout” a supervisory role such that the stored patient care data may notbe nefariously tampered with. Likewise, those of ordinary skill in theart will recognize that appropriate safety measures should beincorporated into any particular implementation, including, for example,waterproofing measures and other electrical safety measures such asinterference shielding.

Additionally, those of ordinary skill in the art will recognize that thesystem and methods described herein for the prevention, treatment andcure of decubitus ulcers may be applied to similar ends such as, forexample, for ensuring that newborn babies are rotated on appropriateschedules, thereby preventing cranial deformations concomitantimmobility during the period of fusion of the cranial joints. In anycase, because the scope of the present invention is much broader thanany particular embodiment, the foregoing detailed description should notbe construed as a limitation of the scope of the present invention,which is limited only by the claims appended hereto.

What is claimed is:
 1. A system for monitoring localized interfacepressures produced between a surface and a patient supported thereon,said monitoring system comprising: an underlayment adapted to beinterposed between a patient support surface and a patient restingadjacent said patient support surface, said underlayment comprising aplurality of pressure sensors; and a processor in electricalcommunication with said pressure sensors of said underlayment, saidprocessor being adapted to: acquire and map pressure data as measured bysaid pressure sensors; store said mapped pressure data; analyze saidstored pressure data for the determination of the body position of thepatient from the group consisting of: the supine position; the proneposition; and a lateral position; and determine, based upon whether thedetermined body position of the patient has remained unchanged, from onesaid body position to another said body position, over a length of timeexceeding an established threshold value, whether repositioning of thepatient should take place.
 2. The monitoring system as recited in claim1, wherein said pressure sensors comprise piezoelectric sensors.
 3. Themonitoring system as recited in claim 2, wherein said piezoelectricsensors are arranged in a sensor array.
 4. The monitoring system asrecited in claim 1, wherein said patient support surface comprises amattress.
 5. The monitoring system as recited in claim 1, wherein saidprocessor is further adapted to transmit a signal indicating a need forcaregiver intervention upon the determined body position of the patientremaining unchanged over a length of time exceeding said establishedthreshold value.
 6. The monitoring system as recited in claim 5, whereinsaid processor is further adapted to create and store an audit recordrecording time spent by the patient in a determined body position. 7.The monitoring system as recited in claim 6, wherein said processor isfurther adapted to create and store an audit record recording time spentby the patient in a determined body position prior to intervention by acaregiver and the identity of the caregiver making the intervention. 8.The monitoring system as recited in claim 7, said monitoring systemfurther comprising a keypad and wherein said keypad and said processorare cooperatively adapted to capture the identity of the caregivermaking the intervention.
 9. The monitoring system as recited in claim 8,wherein said keypad and said processor are further cooperatively adaptedto capture the identity of the caregiver making the intervention byentry of a code through said keypad.
 10. The monitoring system asrecited in claim 7, said monitoring system further comprising afingerprint reader and wherein said fingerprint reader and saidprocessor are cooperatively adapted to capture the identity of thecaregiver making the intervention.
 11. The monitoring system as recitedin claim 10, wherein said fingerprint reader and said processor arefurther cooperatively adapted to capture the identity of the caregivermaking the intervention by capture of a fingerprint.
 12. The monitoringsystem as recited in claim 7, said monitoring system further comprisinga card reader and wherein said card reader and said processor arecooperatively adapted to capture the identity of the caregiver makingthe intervention.
 13. The monitoring system as recited in claim 12,wherein said card reader and said processor are further cooperativelyadapted to capture the identity of the caregiver making the interventionby reading of an identification card.
 14. The monitoring system asrecited in claim 5, wherein said processor is further adapted totransmit, upon passage of an established time following transmission ofsaid signal indicating a need for caregiver intervention, an alarmsignal indicating untimely caregiver intervention.
 15. The monitoringsystem as recited in claim 1, wherein said processor is further adaptedto receive, through a user interface, an adjustment determined by acaregiver based upon patient risk factors to said established thresholdvalue.
 16. The monitoring system as recited in claim 1, wherein saidprocessor is further adapted to reset said length of time to zero inresponse to manual input.
 17. A system for monitoring localizedinterface pressures produced between a surface and a patient supportedthereon, said monitoring system comprising: an underlayment adapted tobe interposed between a patient support surface and a patient restingadjacent said patient support surface, said underlayment comprising aplurality of pressure sensors; and a processor in electricalcommunication with said pressure sensors of said underlayment, saidprocessor being adapted to: acquire and map pressure data as measured bysaid pressure sensors; store said mapped pressure data; analyze saidstored pressure data for the determination of the body position of thepatient from the group consisting of: the supine position; the proneposition; and a lateral position; determine, based upon whether thedetermined body position of the patient has remained unchanged, from onesaid body position to another said body position, over a length of timeexceeding an established threshold value, whether repositioning of thepatient should take place; generate a graphical image of said mappedpressure data; and display, through a user interface, said graphicalimage.
 18. The monitoring system as recited in claim 17, wherein saidprocessor is further adapted to reset said length of time to zero inresponse to manual input.
 19. A system for monitoring localizedinterface pressures produced between a surface and a patient supportedthereon, said monitoring system comprising: an underlayment adapted tobe interposed between a patient support surface and a patient restingadjacent said patient support surface, said underlayment comprising aplurality of pressure sensors; and a processor in electricalcommunication with said pressure sensors of said underlayment, saidprocessor being adapted to: acquire and map pressure data as measured bysaid pressure sensors; store said mapped pressure data; analyze saidstored pressure data for the determination of the body position of thepatient from the group consisting of: the supine position; the proneposition; and a lateral position; determine, based upon whether thedetermined body position of the patient has remained unchanged, from onesaid body position to another said body position, over a length of timeexceeding an established threshold value, whether repositioning of thepatient should take place; transmit a signal indicating a need forcaregiver intervention upon the determined body position of the patientremaining unchanged over a length of time exceeding said establishedthreshold value; generate a graphical image of said mapped pressuredata; and display, through a user interface, said graphical image.